search for: usersplits

Hi, I would like write a split function to implement a new split method with the package RPART. I see that I can define my split function as specified in the example of usersplits function, but I don't understand how I can use the variable "offsets". What is the meaning of these variable? Thank's Michela

Dear all, I'm writing my own method to be used in Rpart by defining the list of functions named init, split and eval. I'm following the example given in the file 'tests/usersplits.R' in the sources. By now I'm able to define the split function (and it works correctly in the tree construction) while I have some problems with the init and the eval function. The task I'm facing with is a classification task and I'd like the eval function to produce an output...

...unctions in rpart, and before I tear my hair out trying to fix it, I want to make sure it's actually a problem. It seems that, when you write custom functions for rpart (init, split and eval) then rpart no longer cross-validates the resulting tree to return errors. A simple test is to use the usersplits.R function to get a simple, custom rpart function, and then change fit1 and fit2 so that the both have xvals of 10. The problem occurs in that the cptable for fit1 doesn't have xerror or xstd, despite the fact that the cross-validation is set to 10-fold. I guess I just need conformation that...

Hi I have installed rpart in my Linux (PLD) but I don't know how I may find help conect this package? Here is my instalaction: > install.packages("rpart",dependencies=TRUE) --- Please select a CRAN mirror for use in this session --- trying URL 'http://r.meteo.uni.wroc.pl/src/contrib/rpart_3.1-46.tar.gz' Content type 'application/x-gzip' length 136572 bytes (133

Dear R community, I am trying to write my own user defined split function for rpart. I read the example in the tests directory and I understand the general idea of the how to implement user defined splitting functions. However, I am having troubles with addressing the data frame used in calling rpart in my split functions. For example, in the evaluation function that is called once per node,

Dear all, I'm trying to manage with user defined split function in rpart (file rpart\tests\usersplits.R in http://cran.r-project.org/src/contrib/rpart_3.1-34.tar.gz - see bottom of the email). Suppose to have the following data.frame (note that x's values are already sorted) > D y x 1 7 0.428 2 3 0.876 3 1 1.467 4 6 1.492 5 3 1.703 6 4 2.406 7 8 2.628 8 6 2.879 9 5 3.025 10 3 3.494 11 2 3...

Hallo! I am a student of the Politecnico di Milano (Milan, italy) and I'm working on CARTs. I'm trying to use the R rpart function with a personalized splitfunction... but I'm not able to do it! More precisely, I would like to know what is the meaning of the function 'init', 'split' and 'eval' named in the help page.I can't find any answer in

...; Fabricius (2000) using sums of absolute deviations about the median as an impurity measure gives robust trees. I would like to use this method in rpart. Has somebody already tried this method in rpart? Is there maybe already a script available somewhere? I am aware of the possibility to define usersplits myself with eval, split and init. As an R beginner, though, I would like to check the existing experience first. Thanks Sina Writing a thesis on "The effects of land-use change on vegetation patterns in a Southern-Alpine valley (Switzerland)" University of Potsdam, Germany Department...

...ctions in rpart, and before I tear my hair out trying to fix it, I want to make sure it's actually a problem. It seems that, when you write custom functions for rpart (init, split and eval) then rpart no longer cross-validates the resulting tree to return errors. A simple test is to use the usersplits.R function to get a simple, custom rpart function, and then change fit1 and fit2 so that the both have xvals of 10. The problem occurs in that the cptable for fit1 doesn't have xerror or xstd, despite the fact that the cross-validation is set to 10-fold. I guess I just need conformation tha...